1. Field of the Invention
This invention relates generally to label applicators, and, more particularly, to an apparatus and method for more accurately applying pressure-sensitive labels to articles.
2. Description of Related Art
As is well known, many articles or products require that some type of adhesive label be applied to the product or packaging therefor, after manufacturing. To meet the different requirements of manufacturers and packagers of such products, many types of apparatus and systems have been proposed and are used. Known types of label applicators include, but are not limited to, air-jet (blow on), synchronous (wipe-on), tamp, corner wrap (similar to wipe-on), flag (wiring cable) and round product applicators.
Many of the known prior art systems use air-assist methods for capturing the label onto a tamp head and applying the label to an article. However, there is a period of time during which the label is xe2x80x9cfree flyingxe2x80x9d in space as it releases from a backing and is drawn by a vacuum onto the tamp head. During this xe2x80x9cfree flyingxe2x80x9d time, the label may easily by moved out of registration.
Other prior art systems use an intermediate device having a non-stick surface that takes the label from the backing surface and moves the label to a tamp head for eventual application to an article. This transfer of the label from the backing strip to the tamp head by the intermediate device also causes registration problems.
A typical label applicator applies one or more labels to an article as the article is conveyed past the label applicator. For example, a label applicator may include a label dispenser, which dispenses a label onto a label receiver or applicator section. The applicator section then transfers the label to the article.
This transfer is often accomplished by a blast of gas, typically air, under applicator section. The applicator section then transfers the label to the article.
This transfer is often accomplished by a blast of gas, typically air, under pressure. Labels used in these label applicators are usually secured to a backing strip by an adhesive, and the backing strip is wound onto a supply reel, fan-folded, or held in some other manner. The backing strip and labels are moved from the supply reel, or other holding area, through a printing area, if included, by a take-up mechanism, such as a reel, and the labels are peeled off of the backing strip by a peel bar, and momentarily retained at an applicator or label receiver. The applicator or label receiver then transfers the label to a passing article.
However, in all of the prior art systems, there is a measurable gap between the peel bar and the applicator, such as a tamp or transfer head, and the printed adhesive-backed label is removed completely from the backing strip, thereby losing the accurate positioning inherent in die cut labels on backing strips.
The apparatus and method of the present invention utilizes the accurate positioning of die cut printed labels on a backing strip by ensuring that a trailing portion of the printed label remains attached to the backing strip at a pickup point. The label remains in its die cut position on the backing strip until a vacuum head removes the label and applies it to a product. Therefore, accurate positioning of the printed label is always maintained, thereby overcoming the known problems with the prior art.
In many industries, such as electronics, smaller and smaller labels are required since surface area on many articles or products is not available or limited. Furthermore, high-resolution printers used to print on the labels to be applied to the products are able to print more condensed bar codes, two-dimensional codes, graphics, and/or wording on such labels. Therefore, accuracy of print location on the label and accuracy of the label placement on the article to be marked are imperative for automatic identification by bar codes, two-dimensional codes, optical character recognition and other vision systems used to keep track of such articles.
The present invention enables increased accuracy, increased throughput by the ability to simultaneously pick up multiple labels, and increased reliability by eliminating intermediate pick up mechanisms. The present invention eliminates the need for back feeding of labels in order to print accurately on all areas of a label, when a print head is used with the system. By eliminating the back feeding, mechanical backlash is eliminated, thereby improving the relative position accuracy of the label, print head and peel bar.
It is, therefore, a general object of the present invention to provide an improved and simplified label applicator. It is a particular object of the present invention to provide an improved and more accurate label applicator. It is another particular object of the present invention to provide an improved label applicator, which may be used with preprinted labels or in print-and-apply systems. It is yet still another particular object of the present invention to provide an improved print-and-apply system having a specifically added peel bar assembly, which peel bar assembly is adjustable and provides the capability for mechanically adjusting the critical distance between a print head and the peel bar, depending on the size of labels to be printed. It is yet a further particular object of the present invention to provide an apparatus and method for ensuring that at least the trailing edge of labels remain attached to a backing strip, and that the labels remain in their die cut position on a backing strip until a vacuum head removes the labels and secures the labels to articles whereby accurate positioning of the label on the articles is always maintained. And, it is a further particular object of the present invention to provide an improved label applicator in which there is no free flying label, intermediate mechanism to transfer labels to a pick up head, or a gap between a peel bar and a tamp head specifically designed to allow the label to be completely peeled from the backing strip for attachment to the pick up head.
These and other objects and advantages of the present invention are achieved by providing an improved label applicator for applying labels to articles.
The label applicator allows at least the trailing edge of labels to remain attached to a backing strip after the leading edge passes over a peel bar. The labels remain in their die cut position on the backing strip until a vacuum head removes the labels from the backing strip and secures them to articles. The improved method and system of the present invention includes an adjustable peel bar cooperating with sensing means that ensure that a leading edge of each label is properly aligned before dispensing or printing, to thereby always provide proper alignment of the labels during printing and dispensing of labels onto articles.